: In a very practical sense antigravity can be considered any force that works against gravity. This definition then would include conventional rocket engines which loft large spacecraft out of Earths gravity well and into orbit or beyond.

: The highly speculative idea that a force in nature or by human design may exist now or in the future is currently unprovable. Despite the tremendous acheivements of this century and an ever expanding knowledge of how the universe works on many levels, we still do not understand how gravity, the most fundamental force in nature, truely works. Lacking this knowledge an opposite to gravity is even further from our understanding.

: However I believe it is worthwhile to exlore and develop energies that mimic the desired effects of antigravity. By examing such phenomena in nature or in the lab we may inadvertently learn more about gravity itself.

: I will add more to this response later. Feel free to correspond with me.